ABSTRACT
Cytogenetic analysis of Iris pumila L. plants from different habitats in Ukraine revealed the intrachromosomal polymorphism. Chromosome number 2n = 32 was established for plants of this species. Root meristem of I. pumila seedlings of all populations showed high level of mixoploidy. The differences in the percentage of aneuploid cells and anaphase aberration were found between the sampled populations. Anaphase analysis revealed the level of chromosomal rearrangements that reached 9.2% in some populations reached.
Subject(s)
Chromosomes, Plant , Iridaceae/genetics , Meristem/genetics , Polymorphism, Genetic , Anaphase , Aneuploidy , Cytogenetic Analysis , Metaphase , Seedlings , UkraineABSTRACT
Genome of Rauwolfia serpentina callus cells was found to fail undergo the noticeable changes for several early passages upon the switch from surface to submerged cultivation in the liquid medium of special composition. After subsequent 4-6 passages in submerged culture RAPD spectra polymorphism was revealed which may reflect the changes in DNA sequence as well as in the structure of cell population that forms the strain. Introduction of the intermediary passage on the agar-solidified medium of more simple composition prior to transfer into liquid medium appeared not to affect essentially the level and the pattern of genome changes.
Subject(s)
Genome, Plant , Plants, Medicinal , Rauwolfia/growth & development , Culture Techniques/methods , DNA Primers/genetics , DNA, Plant/genetics , Immersion , Polymorphism, Genetic , Random Amplified Polymorphic DNA Technique , Rauwolfia/genetics , Secologanin Tryptamine Alkaloids/isolation & purificationABSTRACT
An analysis of 18S-25S and 5S rRNA genes in intact plants and cultured tissues of some Rauwolfia species was performed to compare these sequences variability occurred as a result of the species evolution in nature and that induced by tissue culture. The restriction fragment length polymorphism of 18S-25S and 5S rDNA was found both in intact plants of various Rauwolfia species and in long-term Rauwolfia serpentina tissue cultures. In addition, changes in the amount of 18S-25S rRNA genes were observed in long-term R. serpentina tissue cultures. The results demonstrate that rDNA variability observed in intact plants as well as in long-term cultures is attributed to differences in the same regions of ribosomal RNA genes.
Subject(s)
Gene Rearrangement/genetics , Genes, Plant , Genes, rRNA , Polymorphism, Genetic , Rauwolfia/genetics , DNA, Ribosomal/genetics , Deoxyribonuclease BamHI/metabolism , Polymorphism, Restriction Fragment Length , RNA, Ribosomal/genetics , RNA, Ribosomal, 18S/genetics , RNA, Ribosomal, 5S/genetics , Species Specificity , Tissue Culture TechniquesABSTRACT
In this paper we demonstrate that apoptosis in primary culture of murine thymocytes and in continuously growing human cells is associated with the progressive disintegration of nuclear DNA into high molecular weight (HMW)-DNA fragments of about 50-150 kb. We also show that the formation of similarly sized HMW-DNA fragments takes place in the same cells in the absence of apoptotic inducers. Unlike an apoptotic fragmentation of nuclear DNA, the formation of HMW-DNA fragments in nonapoptotic cells is rapidly induced, has no correlation with the cell death, and is not associated with the development of oligonucleosomal "ladder" or apoptotic changes in nuclear morphology. The disintegration of DNA into HMW-fragments is also observed in nuclei isolated from healthy, nonapoptosizing tissues of various eukaryotes. We show that the formation of HMW-DNA fragments in the absence of apoptotic inducers is strongly dependent on the ionic detergents, is responsive to the topoisomerase II-specific poison, teniposide, and is completely reversible under conditions that favor topoisomerase II-dependent rejoining reaction. Also, we demonstrate that the formation of HMW-DNA fragments in continuously growing cell lines caused either by serum deprivation or monolayer establishment is of a transient nature and rapidly reverses to the control level following serum addition or dilution of monolayer. The results suggest that the cleavage of nuclear DNA into HMW-DNA fragments is associated not only with apoptosis but also accompanies changes in functional activity of nonapoptotic cells.
Subject(s)
Apoptosis , Cell Nucleus/physiology , DNA Fragmentation/physiology , T-Lymphocytes/physiology , Animals , Apoptosis/drug effects , Cell Line , Cell Survival/drug effects , Cells, Cultured , DNA/analysis , DNA/drug effects , DNA, Neoplasm/analysis , DNA, Neoplasm/drug effects , Dexamethasone/pharmacology , HeLa Cells , Humans , Mice , Mice, Inbred BALB C , Molecular Weight , Precursor Cell Lymphoblastic Leukemia-Lymphoma , T-Lymphocytes/cytology , Teniposide/pharmacology , Tumor Cells, CulturedABSTRACT
The data presented confirm the possibility of enzymatic formation of discrete DNA-fragments appearing during fractionation of nuclear DNA by FIGE. Teniposide-dependent pattern of DNA-fragments as well as occurrence of protein-linked DNA breaks suggest that discrete cleavage of intact nuclear DNA is modulated by DNA topoisomerase II. The possible relationship between discrete DNA-fragments and the higher order chromatin folding are discussed.
